Pethidine is a narcotic analgesic with multiple actions qualitatively similar to those of morphine; the most prominent of these involve the central nervous system and organs composed of smooth muscle. The principal actions of therapeutic value are analgesia and sedation.

CONTRAINDICATIONS:

hypersensitivity to pethidine

WARNINGS

Impaired Respiration:
Respiratory depression is the chief hazard of all opioids. Respiratory depression occurs most frequently in the elderly and debilitated patients as well as in those suffering from conditions accompanied by hypoxia or hypercapnia when even moderate therapeutic doses may dangerously decrease pulmonary ventilation.
Pethidine should be used with extreme caution in patients with chronic obstructive pulmonary disease or cor pulmonale, and in patients having a substantially decreased respiratory reserve, hypoxia, hypercapnia, or preexisting respiratory depression. In such patients, even usual therapeutic doses of morphine may decrease respiratory drive while simultaneously increasing airway resistance to the point of apnoea.

Hypotensive Effect:
Morphine sulphate controlled-release tablets, like all opioid analgesics, may cause severe hypotension in an individual whose ability to maintain his blood pressure has already been compromised by a depleted blood volume, or a concurrent administration of drugs that lower blood pressure.

Anaphylaxis:
Although extremely rare, cases of anaphylaxis have been reported.

PRECAUTIONS

General:
Supraventricular Tachycardias
— Pethidine should be used with caution in patients with atrial flutter and other supraventricular tachycardias because of a possible vagolytic action which may produce a significant increase in the ventricular response rate.
Convulsions
— Pethidine may aggravate pre-existing convulsions in patients with convulsive disorders. If dosage is escalated substantially above recommended levels because of tolerance development, convulsions may occur in individuals without a history of convulsive disorders.

Laboratory Tests: No tests in addition to routine ICU tests are indicated

Drug/Laboratory Test Interactions: None noted

IMPORTANT DRUG INTERACTIONS FOR THE ICU

The concomitant use of other central nervous system depressants including sedatives or hypnotics, general anaesthetics, phenothiazines, tranquilizers, and alcohol may produce additive depressant effects. Respiratory depression, hypotension, and profound sedation or coma may occur.